title: Canonical Wnt signaling regulates Nkx3.1 expression and luminal epithelial differentiation during prostate organogenesis.
abstract: BACKGROUND
  The formation of the prostate gland requires reciprocal interactions between the epithelial and mesenchymal components of the embryonic urogenital sinus. However, the identity of the signaling factors that mediate these interactions is largely unknown.
  
  
  RESULTS
  Our studies show that expression of the prostate-specific transcription factor Nkx3.1 is regulated by the canonical Wnt signaling pathway. Using mice carrying a targeted lacZ knock-in allele of Nkx3.1, we find that Nkx3.1 is expressed in all epithelial cells of ductal buds during prostate organogenesis. Addition of Wnt inhibitors to urogenital sinus explant culture greatly reduces prostate budding and inhibits Nkx3.1 expression as well as differentiation of luminal epithelial cells. Analyses of a TCF/Lef:H2B-GFP transgene reporter show that canonical Wnt signaling activity is found in urogenital mesenchyme but not urogenital sinus epithelium before prostate formation, and is later observed in the mesenchyme and epithelium of prostate ductal tips. Furthermore, TCF/Lef:H2B-GFP reporter activity is reduced in epithelial cells of Nkx3.1 null neonatal prostates, suggesting that Nkx3.1 functions to maintain canonical Wnt signaling activity in developing prostate bud tips.
  
  
  CONCLUSIONS
  We propose that activated canonical Wnt signals and Nkx3.1 function in a positive feedback loop to regulate prostate bud growth and luminal epithelial differentiation.
authors.affiliation: Departments of Medicine and Genetics and Development, Columbia University Medical Center, New York, New York; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York.
authors.forename: Marianna
authors.initials: M
authors.lastname: Kruithof-de Julio
authors.forename: Maho
authors.initials: M
authors.lastname: Shibata
authors.forename: Nishita
authors.initials: N
authors.lastname: Desai
authors.forename: Melissa
authors.initials: M
authors.lastname: Reynon
authors.forename: M Vivienne
authors.initials: MV
authors.lastname: Halili
authors.forename: Ya-Ping
authors.initials: YP
authors.lastname: Hu
authors.forename: Sandy M
authors.initials: SM
authors.lastname: Price
authors.forename: Cory
authors.initials: C
authors.lastname: Abate-Shen
authors.forename: Michael M
authors.initials: MM
authors.lastname: Shen
mesh_terms: D000818:Animals; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D038081:Organogenesis / Q000502:physiology*; D011467:Prostate / Q000166:cytology / Q000196:embryology*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D018398:Homeodomain Proteins; C102837:Nkx3-1 protein, mouse; D014157:Transcription Factors; D051153:Wnt Proteins
keywords: epithelial-mesenchymal interactions; prostate development; urogenital sinus